FUS/TLS contributes to replication-dependent histone gene expression by interaction with U7 snRNPs and histone-specific transcription factors

Replication-dependent histone genes are up-regulated during the G1/S phase transition to meet the requirement for histones to package the newly synthesized DNA. In mammalian cells, this increment is achieved by enhanced transcription and 3′ end processing. The non-polyadenylated histone mRNA 3′ ends are generated by a unique mechanism involving the U7 small ribonucleoprotein (U7 snRNP). By using affinity purification methods to enrich U7 snRNA, we identified FUS/TLS as a novel U7 snRNP interacting protein. Both U7 snRNA and histone transcripts can be precipitated by FUS antibodies predominantly in the S phase of the cell cycle. Moreover, FUS depletion leads to decreased levels of correctly processed histone mRNAs and increased levels of extended transcripts. Interestingly, FUS antibodies also co-immunoprecipitate histone transcriptional activator NPAT and transcriptional repressor hnRNP UL1 in different phases of the cell cycle. We further show that FUS binds to histone genes in S phase, promotes the recruitment of RNA polymerase II and is important for the activity of histone gene promoters. Thus, FUS may serve as a linking factor that positively regulates histone gene transcription and 3′ end processing by interacting with the U7 snRNP and other factors involved in replication-dependent histone gene expressio

FUS/TLS contributes to replication-dependent histone gene expression by interaction with U7 snRNPs and histone-specific transcription factors.

Replication-dependent histone genes are up-regulated during the G1/S phase transition to meet the requirement for histones to package the newly synthesized DNA. In mammalian cells, this increment is achieved by enhanced transcription and 3' end processing. The non-polyadenylated histone mRNA 3' ends are generated by a unique mechanism involving the U7 small ribonucleoprotein (U7 snRNP). By using affinity purification methods to enrich U7 snRNA, we identified FUS/TLS as a novel U7 snRNP interacting protein. Both U7 snRNA and histone transcripts can be precipitated by FUS antibodies predominantly in the S phase of the cell cycle. Moreover, FUS depletion leads to decreased levels of correctly processed histone mRNAs and increased levels of extended transcripts. Interestingly, FUS antibodies also co-immunoprecipitate histone transcriptional activator NPAT and transcriptional repressor hnRNP UL1 in different phases of the cell cycle. We further show that FUS binds to histone genes in S phase, promotes the recruitment of RNA polymerase II and is important for the activity of histone gene promoters. Thus, FUS may serve as a linking factor that positively regulates histone gene transcription and 3' end processing by interacting with the U7 snRNP and other factors involved in replication-dependent histone gene expression

MOESM1 of Positive cofactor 4 (PC4) contributes to the regulation of replication-dependent canonical histone gene expression

Additional file 1: Table S1. List of PC4 protein identifications by mass spectrometry

MOESM6 of Positive cofactor 4 (PC4) contributes to the regulation of replication-dependent canonical histone gene expression

Additional file 6: Table S3. Primers used in RT-qPCR to analyze the level of histone transcripts at “TSS region”, “histone body” and “3′ end” regions

MOESM4 of Positive cofactor 4 (PC4) contributes to the regulation of replication-dependent canonical histone gene expression

Additional file 4: Figure S3. Flow cytometry analysis of propidium iodide-stained asynchronous HeLa scramble cells (A) and PC4 knockdown (B). Numbers represent mean value of cells percentage with provided standard deviation value (± SD)

MOESM3 of Positive cofactor 4 (PC4) contributes to the regulation of replication-dependent canonical histone gene expression

Additional file 3: Figure S2. Flow cytometry analysis of propidium iodide-stained HeLa cells with PC4 overexpression (A) and PC4 knockdown (B) after synchronization. Graphs represents number of cells synchronized to G1 (upper panel) or to S phase (lower panel) to Yellow-B fluorescence intensity. Grey color on the histogram symbolizes asynchronous cells

MOESM5 of Positive cofactor 4 (PC4) contributes to the regulation of replication-dependent canonical histone gene expression

Additional file 5: Table S2. Oligonucleotides cloned into pLKO-Tet-On plasmid used for inducible gene knockdown in HeLa cells